The present invention relates generally to a technique for expanding tubing, such as tubing utilized within wellbores, and particularly to a technique utilizing an expansion device moved through the tubing.
A variety of devices are used to expand certain types of tubing from a smaller diameter to a larger diameter. Tubulars, such as those used within wellbores drilled for the production of desired fluids, are sometimes deformed within the wellbore. Typically, the tubing is moved to a desired wellbore location and then forced to a radially expanded condition with an expansion tool.
An exemplary existing expansion tool is a solid conical mandrel designed to be forced through the tubing to obtain the desired expansion. One problem occurs, however, when such devices must be moved through constrictions in the wellbore. The constriction potentially can impede or prohibit passage of the tool. Another problem can occur in attempting to expand the tubing to conform to xe2x80x9cwashoutsxe2x80x9d or other expanded regions in the wellbore. Existing tools are unable to conform to distorted tubular cross-sections. It would be advantageous to have a technique adapted to expand desired tubulars while allowing conformity to such perturbations within the wellbore.
The present invention features a technique for expanding a tubular structure, such as a tubular utilized in a wellbore environment. The technique utilizes an expansion mechanism that works in cooperation with the tubular structure to increase the diameter of the tubular structure upon placement at a desired location. The expansion device has an expandable mandrel that may be selectively actuated between a contracted state and an expanded state. The expansion device has a plurality of independently movable components that allow it to conform to a variety of cross-sectional configurations as it is moved through the tubular structure.